DD265882A1 - PROCESS FOR PRODUCING MODIFIED HYDRATED SODIUM RIPHOSPHATE - Google Patents

Abstract

The invention relates to a process for the preparation of hydrated sodium triphosphate, in particular for use in detergents. The aim of the invention is to develop a process for the preparation of hydrated sodium triphosphate, in which a free-flowing, non-caking product with high utility value is formed and hydrolysis reactions during hydration are avoided. According to the invention, the process for producing hydrated sodium triphosphate is characterized in that, on a moving solid bed of anhydrous sodium triphosphate, 1% by weight of phosphonic acid and / or alkali metal phosphonates as solids plus water and / or as aqueous solutions up to a water content of the finished product of 0.5 -21% by weight.

Description

Field of application of the invention

The invention relates to a process for the preparation of hydrated sodium triphosphate, in particular for use in detergents.

Characteristic of the known technical solutions

The main problem in producing hydrated sodium phosphate from an anhydrous product and water is that it is difficult to effect a uniform hydration, as a result of which the product may still contain water freely, as a result of what will later be described. Finally, hydration leads to clumped products. Another disadvantage is that the hydration reaction is a strongly exothermic reaction. The temperature in the hydrated sodium triphosphai may locally rise so high that conversion to other phosphates occurs by hydrolysis. There are several ways in which attempts have been made to overcome these difficulties. According to US-PS 3,046,092 is hydrated while stirring the product with ice, while the temperature is kept low and the hydration is relatively uniform. According to this method, the hydrolytic disintegration of the sodium triphosphate could be reduced, but apart from the inefficiency of the admixture of the ice, the uniformity of the end product largely depends on the degree of mixing of the two components. Accordingly, the method has nowhere enforced.

Another procedure is to be taken from the state of the art according to DE-OS 1,792,158. This process is carried out with an excess of water of up to about 30% (based on the stoichiometric amount of water required to form the hexahydrate), to about 50% of the latent heat of evaporation of the excess water, the temperature of the reaction mixture to BO C * u hold. This method has energetic advantages and, moreover, simplifies the process, but partial agglomeration of the powder occurs with partial agglomeration. As a result, the heat exchange is inevitably significantly disturbed, so that the partially moist, hot and lumpy mass tends to partial hydrolysis to form di- and monophosphate.

In DD-WP 103.871 a process for the preparation of hydrated sodium triphosphate is described, which is characterized in that on solid sodium triphosphate> 1 wt .-% sodium sulfate, preferably 10-30Ma .-%, based on the amount of anhydrous Natri.mtriphosphat added and then the reaction mixture is sprayed with water or sodium sulfate solution. In this case, the sodium sulfate acts at higher temperatures by melting in its own water of crystallization after Art elnar .Innenkühlung * and thereby prevents leading up to the undesired range of hydrolysis increasing the reaction temperature. A disadvantage of this process variant is, above all, a significant increase in the required hydration times.

According to DE-OS 3,128,079, a hydrogenated sodium triphosphate is prepared with the addition of 0.01 to 2.0% by weight of calcium or magnesium or zinc or strontium ions. This specifically changes the hydration time and temperature. On the one hand, the presence of these ions abolishes the inherent tendency of the partially hydrate-containing triphosphate to form a highly volatile slurry, but on the other hand does not slow down the rate of hydration by these metal ions, resulting in incomplete water binding. As a serious drawback, however, a reduction in the performance properties, with regard to the ability of the sodium triphosphate Ca ⁺ * and Mg ⁺ * as well as further to mask cations in hard water, must be considered.

Goal dt * invention

The aim of the invention is ns to develop a process for producing hydratishrtem sodium triphosphate, in which a rieselfähfgos non-caking product is and with high practical value e "" hydrolysis reactions are avoided in the hydration.

-2- 265 832

Explanation of the essence of the invention

The object of the invention is to develop a technologically simplest and continuous process for the preparation of hydrated sodium triphosphate in which the hydration of the sodium triphosphate takes place while avoiding high temperature peaks, which means that hydrolysis reactions of the phosphate to di- and monophosphate are prevented and at the same time the rate of hydration is increased. The problem could be solved überraischenderweise., That a simple process for the preparation of hydrated sodium triphosphate is used, which is characterized in that on a odor in a rotary kiln on a granulating or in a fluidized bed, etc. produced, moving solid bed of anhydrous sodium triphosphate 1-15Ma .-% phosphonic acids or their alkali metal salts or mixtures of phosphonic acids with one another or non-alkali metal phosphonates as a solid, aqueous suspension or aqueous solution or combined to a water content of 0.5-21 wt .-%, based on the Final product, to be abandoned. The process parameters are adjusted so that the end product preferably 2-10Ma .-% phosphonic acids or phosphonates or mixtures thereof. As phosphonic acids and their alkali metal salts are preferably Aminotris- (methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, Äthyle.ndiamintetra- (methylenphosplionsäure). Hexamethylenediaminetetra (methylenephosphonic acid) and Diäthylentrlaminpenta-fmethylenphosphonsäure) used. Comparisons of the erfindungsgomäß proposed method variants with the treatment of anhydrous Natriurntriphoephat with pure water showed significant differences in temperature increase per unit time during hydration. Thus, the temperatures in the pure water treatment of Na ₆ P ₃ Oi _{0 were} up to 50% higher than in the treatment with aqueous phosphonic acids and their alkali metal salts. The higher the proportion of water sprayed on (in the form of water or as aqueous phosphonic acid solution), the greater was the temperature difference between the two process variants. In the method according to the invention, the spraying of aqueous phosphonic acid solutions had a particularly advantageous effect. In this process variant, the hydration time, based on the treatment of Na ₆ P ₃ OiO with pure water, partially shortened to a quarter, while avoiding temperature peaks. The incorporation of phosphonic acids and / or their alkali metal salts not only results in favorable process engineering, the hydration of anhydrous sodium triphosphate, but as a result of this combination process - polyphosphate / phoephonic acid or phosphonate - also produces products with unique properties for the purposes of water treatment and in the washing and cleaning process. Significant cost savings result from the partial or complete replacement of other products. Especially in the washing and cleaning process, the phosphate content can be significantly reduced by the use of the hydrated sodium triphosphates prepared according to the invention with the same or even improved performance characteristics. Thus, the complex binding capacity and detergency of the detergents are increased, in particular, the regrind of the laundry is reduced. Further improvements in the use properties relate to the release properties and the flowability of the product. Last but not least, the use of the product according to the invention in the washing and cleaning process has the effect of significantly reducing the phosphate balancing of household wastewaters

 The invention will now be explained in more detail by means of exemplary embodiments.

example 1

Anhydrous sodium triphosphate was used on one; Granulated dish within 1 mh with 6%, 12% and 20% water, lied on sodium triphosphate used, sprayed. For each experiment, about 150 g of the sample was placed in a thermally insulated container and the running hydration was monitored by recording the temperature-Zel (curve).

Time Temperature course with the addition of 12% H, 0 20% H ₂ O 6% H ₁ O 24.6 "C 25.3 ⁰ C 0 25.7 ⁰ C Ausgangsma- terialtemp. before loading spray 49.8 "C 62.7 ⁰ C 1 min 39.3 ⁰ C 50.0 "C 65.7 ⁰ C 2 min 42.0 "C 51.8 "C ee.rc 3 min 42.8 ⁰ C 62.2 ⁰ C 66.4 ° C 4 min 43.O ⁰ C 62.4 ⁰ C 64.8 ⁰ C 5 min 42.9 "C 52.2 ⁰ C 63.8X SMIN 42.8 ⁰ C 51.8 ⁰ C 63.3 ⁰ C 7 min 42.5 ⁰ C

Example 2

Anhydrous sodium triphosphate was added 10Ma% Na ₂ SO ₄ based on the anhydrous sodium triphosphate and mixed. 20% of water, based on the sodium triphosphate used, was sprayed on a granulating plate within one minute. To record the temperature-time curve was as in Example 1 procedure.

The following values were measured: Time temperature course with addition of

20% H ₂ O

0 25.1 X Auegans "<material temp

 before spraying

1 min 30.1 ⁰ C

2 min 30.8 ⁰ C

3 min 31.4 "C • 4min 31.9X

5 min 32.5 ⁰ C

β min 32.7 ⁰ C

7 min 33.1 X

8 min 33.6 ⁰ C

9 min 34.2 ⁰ C 1 Omin 34.9 X 1 Imin 35.5 X 12min 36, OX 13min 36, OX

14min 35.7x

Example*

Anhydrous sodium triphosphate was sprayed on a granulating plate within 1 min with a 33.1% aminotris (methylenephosphonic acid). The Menr Pi were calculated so that the sodium triphosphate after hydration contained 6%, 12%, and 20% K1.40% as in Example 1. 150 g of the sample were placed in a thermally insulated vessel and the temperature-titered Kiirve was recorded during the Hydrata _u i.

Time Temperature course with addition of aminotris- (methylenephosphonaaure), 12% crystal 20% crystal Hergostel h .vu was a triphosphate with water water 8% crystal 25.5X 25.5X wnsser 39.0X 46.2 X 0 24.5X 39.5 X 46.1X 1min 33.2 X 39.4X 45.8 X 2 min 33.2 X 39.2 X 45.5X 3 min 33, OX 39, OX 45.2 X 4 min 32.9X 38.7X 44.9X 5 min 32.8X 6 min 32.5 X

Example 4

Anhydrous sodium triphosphate was sprayed on a granulating plate with a 15% tetrasodium aminotrine (methylene phosphonic acid) solution. The amount was calculated so that the sodium triphosphate after hydration contained 6% of water of crystallization. 150 g of the sample was added to the heat-filtered vessel and the hydration was monitored on the temperature-time curve. The measured values are listed in the following table.

Time temperature course of both addition of a 15% sodium salt salt of the Aminotris- (methylenephosphonslure) (end product contained 6% Krlstallwasser)

0 24.4X 1min 28.3 times 2 min 28.6X 3 min 28.9X 4 min 29, OX 5 min 29.2 X 6 min 29.6X 7 min 29.7X 8 min 29.9 X 9 min 30, OX 10min 30.3 X 19 min 31 2 X as temperaure tip

example

Anhydrous sodium triphosphate was mixed with 5% ethylenediaminetetra (methylenephosphonic acid) and sprayed on a granulating plate within 1 minute with a 38% 1-hydroxyethane-1,1-diphosphonic acid. The final product contained 6% and 12% Kristallwaeser after spraying. The course of hydration was then followed by the recorded temperature-time curve. For this purpose, as in the previous examples, 160 g of sample were placed in a thermally insulated vessel

Time Temperature course at 12% water of crystallization 6% crystal water 25.4 ⁹ C 0 25.1 "C RSY / c 1 min 32.8 ⁰ C 3i \ 0 ° C 2 min 33.0 ⁰ C 38.7 ⁰ C 3 min 32.9 "C 38.4 ⁰ C 4 min 32.7 ° C 38, ⁰ ° C 5 min 32.4 ⁰ C 37.7 ⁰ C 6 min 32.1 ⁰ C

Examples

Anhydrous sodium triphosphate was sprayed in a rotary drum with a 48% Amniotris (methylenephosphonic acid) within one minute. The amount was calculated so that the sodium triphosphate after hydration contained 21% of water of crystallization. 150g of the sample was placed in a heat insulated vessel and hydration was monitored by temperature-time curve. The following measured values were determined:

Time course of temperature when adding a

48% igAnAmino (RIS (mothylenphosphonsäure)

0 1min

2 min

3 min

4 min

5 min

6 min

Claims (2)

1. Verfahrer, mr production of modified hydratiieitem sodium triphosphate, characterized in that on a moving solid bed of anhydrous sodium triphosphate 1 to 15Ma .-% phosphonic acids and / or Alkaliphosphonate as solids plus water and / or as aqueous solutions up to a water content of the final product of 0 , 5-21% by weight. 2. The method according to claim 1, characterized in that preferably as phosphonic acids or PhosphonsäuregemischeAmototris-fmethylenphosphonsävire), i-hydroxyethane-1,1-diphosphonic acid, ethylenediaminetetra-imethylenphosphonsüure), Hexamethylendiamintetra- (methylenephosphonic) and Diäthy) entriaminpenta- (methylenephosphonic) or whose alkali metal salts are used.